Induction-coil



(No Model.)

J. RITCHIE.

INDUCTION COIL No. 363,851. Patented May 31, 1887.

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I l l UNITED STATES PATENT OFFICE.

JOHN RITCHIE, OF BROOKLINE, MASSACHUSETTS.

lNDUCTlON-COIL.

SPECIFICATION forming part of Letters Patent No. 363,851, dated May 31, 1887.

' Application filed July 30, 1886. Serial No. 209,506. (No model.)

To all whom it may concern:

Be it known that I, J OHN RITCHIE, a citizen of the United States, and alresident of Brookline, in the county of Norfolk and State of Massachusetts, have invented a new and useful Improvement in Induction-Coils; and I hereby declare the same to be described in the following specification, and represented in the accompanying drawings. v

My invention relates to the construction of a spool upon which to wind the secondary helix ofthe induction-coil, the object being toohta-in sufficientinsulation betweenportions of the wire of which the helixis made without interposinginsulatingdisks orringssurrounding the centralcylinder,theinteriorof which islessthan the interior diameter of the sections of the conducting-wire, as has heretofore been done to prevent an electrical discharge across from one section of the wire to the adjoining section, thus bringing the primary and the secondary helices into closer proximity, and thus increasing'the electrical tension in the secondary helix.

To this end I make a spool, consisting of a cylinder with heads and with one or more ridges, of one piece of vulcanite or other suitable insulating material, forming spaces for winding the insulated wire. I

Figure 1 is a top view of a spool having three ridges, in which A A is the cylinder, B B the head, and G O (l are three ridges. Fig. 2 is a vertical section of the spool with the spaces D D D D filled with wire, and within the cylinder the primary helix and the core of iron, which, excited by a battery-current, induces an electrical current in the wire of the secondary helix. Fig.3 is transverse section through one of the spaces between the ridges filled with wire.

In winding a helix I pass the end of a quantity of insulated wire through a hole in the ridge, as at e, and as the spool is revolved I lay the wire in courses, as an ordinary spool of sewing'thread is wound, until the space D is nearly filled, butleaving the ridge 0 extending above enough to prevent an electrical discharge over it. rily securing the end. I thenjoin a quantity of wire to the first end projecting through the ridgee, and, reversing the direction of revolution of the spool, I proceed to nearly fill the space D adjoining the first. In like manner I fill two adjoining spaces,D D ,continuing, it there are more spaces, until all are filled. I then solder together the outer ends of the wire of adjoining spaces over or preferably through holes drilled near the edges of the dividingridge, as at E, and pass the extreme ends of the wire through holes'drilled through the heads ofthe spool m n. It is evident that an I then cut the wire, temporaelectrical current flowing through the whole length of the wire must pass around the spool through every spire in the same direction.

.Wound in this manner, the insulation of the covering of the wire is enough to prevent any discharge of electricity between portions of the wire within either of the spaces, and the insulation of the ridge preventssuch discharge between portions of the wire of adjoining spaces.

What I claim, and desire to secure by Letters Patent of the United States, is-

In an induction-coil, the combination of a spool or cylinder formed of vulcanite or other insulating material and having. a ridge or ridges integral therew ith,'with the conducting-wire of the secondary helix, substantially as set forth.

JOHN RITCHIE.

Witnesses: A. M. RIToHIE, R. O. WHrrFoRD. 

